Using Xcode 6 GM seed my code completion has stopped working. It was working the other day. I was trying to get the unwind segue work around to work. I had made an Objc header file and assigned it as a header for a Swift class.
At this point I get code completion with an Objective-c project. But, not with a Swift project.
I have tried restarting Xcode, making a new empty project.
Best Answer
Just go in
user->Library->Developer->Xcode->DerivedDataand delete the Data of folder(Derived data) and restart Xcode.